Single or multiple switch assembly with single magnet biasing

ABSTRACT

A RELAY CONSISTING OF A PAIR OR PAIRS OF MAGNETICALLY POLARIZED SWITCHES HAVING A SINGLE BIASING MAGNET PER PAIR OPERATED BY A COMMON COIL, OR MULTIPLES OF THESE ASSEMBLIES IN A COMMON RELAY. THE SINGLE BIASING MAGNET FOR EACH PAIR OF MAGNETICALLY POLARIZED SWITCHES IS UTILIZED IN SUCH A MANNER THAT THE LOCATION AND VARYING MAGNETIC CHARACTERISTICS OF THE MAGNET PROVIDE EASY ADJUSTMENT FOR SINGLE-SIDE-STABLE OR BI-STABLE OPERATING CHARACTERISTICS. WHEN IN PLURALITY FROM ADJACENT ENDS OF PERMANENT MAGNETS ARE OF LIKE POLARITY.

Jan. 26, 1 971 C. M. EMMONS SINGLE OR MULTIPLE SWITCH ASSEMBLY WITH SINGLE MAGNET BIASING 3 Sheets-Sheet. 1 I

Filed June 17, 1968 @0322 507' I C/gyiaaflfiwmws' 7! /3mM7i e7/ w Jan. 26, 1971 c. M. EMMONS 3,559,122

SINGLE OR MULTIPLE SWITCH'ASSEMBLY WITH SINGLE MAGNET BIASING Filed June 17, 1968 3- Sheets-Sheet 3 Q N N N w \{Q Q N 2172067250 I N CZyfaw Mfmmans' Jan. 26, 1971 Y C. M. EMMONS SINGLE 0R U TIPLE SWITCH ASSEMBLY WITH S LE MAGNET BIASING Filed J1me 17. 1968 v fnaarzZvr W M vz m 3 Sheets-Sheet 3 United States Patent 3,559,122 SINGLE OR MULTIPLE SWITCH ASSEMBLY WITH SINGLE MAGNET BIASING Clayton M. Emmons, Elkhart, Ind., assignor to The Adams & Westlake Company, a corporation of Illinois Filed June 17, 1968, Ser. No. 737,750 Int. Cl. H01h 51/22 US. Cl. 335-78 16 Claims ABSTRACT OF THE DISCLOSURE A relay consisting of a pair or pairs of magnetically polarized switches having a single biasing magnet per pair operated by a common coil, or multiples of these assemblies in a common relay. The single biasing magnet for each pair of magnetically polarized switches is utilized in such a manner that the location and varying magnetic characteristics of the magnet provide easy adjustment for single-side-stable or bi-stable operating characteristics. When in plurality form adjacent ends of permanent magnets are of like polarity.

The present invention is directed to new and useful improvements in relay switches of the type in which magnetically polarized switches are operated from a coil. Relays of this class are sometimes used on printed circuit boards.

Heretofore, when relays of this general type included two switches operated from a single coil, each switch of the relay had at least one permanent magnet associated with each such switch. In relays of this type the magnet or magnets were charged and then unbalanced in order to properly condition the relay for a single-side-stable or bi-stable operating characteristics. It should be understood that the term bi-stable as used herein refers to a switch where the armature contacts of the switch stay in the last previously energized position, while the term single-sidestable refers to a switch in which the armature contact returns to the initial position it occupied before energization by the coil. With this invention it has been discovered that relays of this type may be manufactured and properly operated with only a single magnet for each pair of switches of the relay while using adjustment of the single permanent magnet for each pair of switches to achieve single-side-stable or bi-stable switching characteristics for that pair of switches, in addition to obtaining selected sensitivity characteristics. Furthermore, when in pluraliy form adjacent ends of permenant magnets are of like polarity.

Furthermore, a magnet can be used with a single switch and selective adjustment of the magnet determines the operating characteristics of the switch.

Through use of the single permanent magnet for the plural switch relay as disclosed herein, assembly of the complete relay is simplified, magnetic biasing of the relay is simplified, the stability of the relays is improved with respect to their established characteristics of the values of currents to the relay coil which demand operation or release of the switches, and costs of manufacturing the relay may be reduced.

These and other purposes and advantages of the invention will become more apparent in the course of the ensuing specification and claims, when taken with the accompanying drawings, in which:

FIG. 1 is a top view of a typical relay switch assembly incorporating the principles of the present invention and in which a single magnet is associated with a pair of switches housed within a relay coil;

FIG. 2. is a front view of the assembly illustrated in FIG. 1;

3,559,122 Patented Jan. 26, 1971 FIG. 3 is an exploded view illustrating the manner of manufacturing relays in accordance with the principles of the present invention;

FIG. 4 is a top view of a relay assembly comprised of a plurality of switch pairs, having a single magnet per pair of switches, with a common coil, and utilizing the principles of the present invention;

FIG. 5 is a top view of another form of relay assembly utilizing a plurality of coil and switch subassemblies of the type shown in FIG. 1 but supported in a common frame.

FIG. 6 is a top view of a relay of the type shown in FIG. 1 with the position of the permanent magnet changed from that illustrated in that figure; and

FIG. 7 shows still another manner in which a plurality of plural switch groups can be mounted for operation by a single coil.

With specific reference now to the drawings, wherein like elements are designated by like characters throughout, and in the first instance to FIG. 1, the numeral 20 generally designates a relay casing of iron or magnetic material which serves as a cover for the relay assembly positioned therein. The coil of the relay is designated at :21. A first switch 21a has a pair of pole pieces 22 and 23 which are connected to electrical leads 24 and 24a in the base of the relay. A second switch 21b has a pair of pole pieces 25 and 26 which are connected to leads 27 and 27a in the base of the relay. As shown, each switch is of a type having an armature 21c (FIG. 3) which is movable into selective engagement with contacts provided on the associated pole pieces. The armature and contacts are within a glass or glass-like enclosure. The pole pieces project from the end of the enclosure and may or may not project beyond one end of the coil.

The pole pieces and armature of each switch are formed from a magnetic material such as a nickel-iron alloy. One end of the glass envelope is sealed around the pole pieces while the other end of the envelope is sealed around the armature stern assembly and a portion of this assembly projects beyond the glass envelope. A ceramic spacer may be positioned between the pole pieces at the inner wall of the envelope. A body of mercury is introduced into the envelope during the manufacturing process, and, through capillary action, the armature and the contacts of the pole pieces are kept wetted with mercury. The armature and portions of the pole pieces within the envelope may have special configurations to enhance the performance, reliability and operating sensitivity of the relay. Relays as thus described are known to the art and are discussed in a number of patents and publications, including US. Pat. No. 2,609,464 and US. Pat. No. 3,054,873, which disclosures are hereby incorporated by reference.

The armature 21c of each switch is adapted for selective engagement with one or the other of the contacts under the influence of electrical flux from coil 21. Leads 28 and 28a are connected to the armatures of the respective switches. Leads 29 are energizing leads for the coil of the relay assembly. The pole pieces of the two switches are arranged on opposite sides of a cylindrical magnet 30. The opposite poles of the magnet are at the opposite ends thereof. The magnet may have other shapes. The permanent magnet 30 may be made of Alnico or other equivalent magnet material. An insulating sleeve 31 surrounds magnet 30 and magnet 30 may or may not be bonded to the insulation 31. Other means of insulating the magnet from the pole pieces may be employed. The insulating material 31 may or may not be bonded to the pole pieces 22, 23, 25 and 26 of the switch assemblies after assembly, but if not bonded there should be a snug fit. The insnlat ing material may be formed from a polyvinylchloride plastic or other material suitable for insulating purposes.

The operating coil 21 as well as the switches 21a and 21b utilized in the assembly are conventionally formed.

In manufacturing relays in accordance with the present invention, a permanent magnet 30 (see FIG. 3) is assembled with its insulator 31 and the coil 21 is positioned over the switches 21a and 21b. The switches are so arranged that a horizontal line through the pole pieces of one switch standing upright is parallel to a horizontal line through the pole pieces of the other switch standing alongside and also in upright position. The switches are then inserted into the coil, and the permanent magnet with its insulation is placed between the pole pieces of the switches so that the longitudinal axis of the magnet is parallel to the horizontal lines through said pole pieces. The magnet is then positioned along its longitudinal axis so that its end faces are equidistant from the pole pieces, that is to say, a line bisecting the longitudinal axis of the magnet coincides with a line bisecting the distance between the pole pieces of the switches.

It may be noted that each switch enclosure carrying the pole pieces and armature is generally cylindrical in form so that when positioned side by side, as is seen in the finally assembled view at the upper left of FIG. 3, they are received snugly within the operating coil 21.

After the switch assembly is formed as illustrated in FIG. 3, one or the other of the poles of each switch is in contact with the armature.

With the magnet being magnetized along its longitudinal axis, final biasing of the assembly is achieved by moving the magnet horizontally between the pole pieces as indicated at FB of FIG. 3 and/or demagnetizing the magnet somewhat in an electrical field E until the desired sensitivity and operating characteristics are obtained. In speaking of demagnetization, it is intended that the strength of the permanent magnet is to be reduced in a controlled manner either by a magnetic field of opposite polarity or an alternating field. The sensitivity may be checked by energizing the relay coil.

The magnet, during this stage of manufacture, is deliberately made to have a snug fit with respect to the associated pole pieces so that proper adjustment can be made in adjusting to desired operating characteristics and, once its proper position is determined, it is thereafter locked in place either by application of a suitable adhesive, or by the potting operation hereinafter described.

A relay having single-side-stable characteristics has an off-center magnet position as illustrated in FIG. 6. Since the greatest concenrtation of flux is at the end faces of the magnet, the pole pieces closest to an end face have stronger attraction to the armatures than those pole pieces which are not in close proximity to an end face. The contacts of the pole pieces which have the greatest concentration of flux are by reason thereof normally closed contacts, while the contacts of the pole pieces that have a lesser concentration of flux are the normally open contacts. The polarity of these pole pieces, although not magnetically equal in strength, are of opposite polarity. When coil 21 is energized with proper magnitude and polarity, the polarity of the flux that the coil imposes on the armatures, in the area of the contacts, is of the same polarity as that of the normally closed contacts and of opposite polarity to that of the normally open contacts. Therefore, the armatures are repelled by the normally closed contacts and attracted by the normally open contacts, and move into engagement with the normally open contacts.

When the magnet is positioned for bi-stable operating characteristics, as when generally centered with respect to the pole pieces as illustrated in FIG. 1, the magnetic flux of the permanent magnet is somewhat equal to each pole piece of switches 21a and 21b and the armature will engage one or the other of the contacts on the pole pieces. When the coil 21 is energized with proper magnitude and polarity, the vflux of the coil imposes a polarity on the armatures, in the area of the contacts, such that the armatures will be repelled by one set of contacts while being attracted by the other set of'contacts. Conversely, if the coil is energized with the opposite polarity, the armature will move in the opposite direction into engagement with said other set of contacts. The armatures, therefore, will move into engagement with the contacts towhich they are attracted. 'Hencc, since the placement of the permanent magnet is such that the magnetic flux of the magnet is somewhat equal for each pole piece of switches 21a and 21b, the armatures will remain latched in their last operated position when the coil flux is removed.

The degree of sensitivity of the relay may, of course, be adjusted by adjusting the position of the magnet slightly along its longitudinal axis so as to insure balanced biasing forces when a bi-stable operation is desired or to allow some slightly greater bias toward one contact or the other without having enough of an imbalance to cause single-side-stable operation. In such a case, unequal pickup values may be assigned for the two polarities. Similarly, the position of the magnet may be adjusted endwise to provide varying sensitivities of bias in one direction or the other when the magnet is positioned for single-sidestable operation. In some cases, both demagnetization and endwise adjustment may be used to establish the desired operating characteristics and sensitivity of the relay.

When relays are made in the form as illustrated, they may easily be positioned within a casing as illustrated at 20 in FIG. 2 and then the casing is filled with an epoxy, polyurethane or other potting material.

Relays in the form as illustrated herein can also be made up into assemblies of plural pairs of switches as depicted in FIGS. 4, 5 and 7. In FIG. 4, for example, a single elongated coil 33 has a plurality of switch and magnet assemblies 34 positioned therein side by side, preferably with the magnet polarities as shown. Electrostatic shielding material can be applied between each switch or pairs of switches in the group. Relays are thus formed by simply positioning plural switch and single magnet units side by side within a common operating coil. Relays can also be assembled in a package by utilizing the subassembly form illustrated at C in FIG. 3 and then positioning these subassemblies side by side in a casing 35, as shown in FIG. 5, in which case electromagnetic shielding may or may not be provided between each of the subassemblies. Relays may also be formed while using principles disclosed herein by positioning plural groups such as two or more such plural switch and magnet subassemblies 36 within a single circular electrical coil 37, as illustrated in FIG. 7. The principles may be applied also to plug-in type relays.

It should be noted that in the forms of the invention shown in FIGS. 4 and 7, the switch groups being operated by a common coil may be either single-side-stable, bistable, or a combination of the two types. By reason of the fact that the selected operating characteristics of each switch can be made by endwise adjustment of the magnets, both bi-stable and single-side-stable switches may be easily assembled within the common operating coil.

Whereas I have shown and described an operative form of the invention, it should be understood that this showing and description thereof should be taken in an illustrative or diagrammatic sense only. There are modifications to the invention which will fall within the scope and spirit thereof and which will be apparent to those skilled in the art. The scope of the invention should be measured only by the scope of the hereinafter appended claims.

I claim:

1. The method of manufacturing a magnetically biased relay switch including the steps of assembling a pair of switches within an electrical coil, each switch having a pair of pole pieces and an armature and positioned so that each pole piece of one switch is equidistantly spaced from a pole piece of the other switch, positioning a magnet alongside and between the pole pieces with insulation between said magnet and pole pieces, and with a line between the poles of said magnet generally parallel to a line through the pole pieces of each switch, fixing the member within said insulation, and adjusting the axial position of the magnet along a line parallel to a line through the pole pieces of each switch and essentially perpendicular to the longitudinal axis of each switch, to adjust the degree of permanent magnet bias with respect to said pole pieces in order to achieve a desired degree of sensitivity and operating characteristics of the relay.

2. The method of claim 1 characterized by and including the step of shifting the axial position of the magnet to a position wherein the bias produced thereby is suf ficiently great as to cause single side stable operation of the switches.

3. The method of claim 1 wherein the adjustment of said magnet is such as to produce a larger amount of magnetic bias towards one pole piece of each switch while the switches retain bi-stable characteristics.

4. The method of claim 1 characterized by and including the step of encapsulating the coil, switch and magnet assembly following adjustment of the position thereof.

5. The method of claim 1 wherein a plurality of switch assemblies, each of which has a magnet as recited, are assembled side by side within a common coil.

6. The method of claim 1 wherein the magnet of at least one switch assembly is positioned to cause its switches to have single-side-stable operating characteristics while the magnet of at least one other switch assembly is positioned to cause the switches of that assembly to have bi-stable operating characteristics.

7. A relay switch assembly including an electrical operating coil, a switch element positioned within said coil, said switch element including a movable armature between a pair of pole pieces and a permanent magnet positioned alongside said pole pieces, said permanent magnet having insulation to insulate said magnet from said pole pieces, said magnet having the opposite poles thereof positioned so that a line between the poles thereof is parallel to a line through the pole pieces of the switch element and spaced therefrom, one magnet pole being spaced from one pole piece by a distance greater than the spacing of the other magnet pole from the other pole piece.

8. A switch assembly as set forth in claim 7, characterized by and including a pair of switch elements positioned within said coil and each having pole pieces, the switch elements being positioned so that each pole piece of one switch is equidistantly spaced from a pole piece of the other switch, said permanent magnet being located between the pole pieces of the pair of switch elements in a position such that a line between the poles of said permanent magnet is generally parallel to a line between the pole pieces of each switch element.

9. A relay assembly including a hollow electrical operating coil and a plurality of pairs of armature type switch elements within said coil, each switch element having a pair of pole pieces for selective contact with a movable armature in the switch, the pole pieces of each element in each pair being spaced from and aligned with the pole pieces of the other element in the pair, each pair of switch elements. having a permanent magnet positioned between the pole pieces of the switch elements of the pair and positioned so that a line between the poles of the permanent magnet is generally parallel to a line between the pole pieces of each switch element associated therewith.

10. The assembly of claim 9 wherein the magnets of each pair of switch elements are formed and arranged so that at least one pair of switch elements has single-sidestable operating characteristics and at least one other pair of switch elements has bi-stable operating characteristics.

11. A relay assembly as set forth in claim 9 wherein the magnet of at least one pair of switch elements is positioned so that one magnetic pole thereof is spaced from one pole piece of at least one switch element associated therewith by a distance greater than the spacing of the other magnetic pole from the other pole piece of that switch element.

12. The method of manufacturing and adjusting operating characteristics of an armature type electrical relay which uses electrically applied magnetic flux which is imposed upon pole pieces to selectively activate an armature having an end between contact faces of the pole pieces including the steps of assembling a glass-like envelope with pole pieces projecting from one end of the envelope and an armature within the envelope with an electrical operating coil, positioning a single magnetic biasing magnet alongside the projecting ends of the switch pole pieces with a line between the centers of the poles of the magnet generally parallel to a line between the centers of said pole pieces while spaced therefrom and with the longitudinal axis of the magnet being substantially perpendicular to the longitudinal axis of the relay, the position of the magnet being such that the opposite poles of the magnet impart opposite magnetic polarities to said pole pieces, and then changing the position of said magnet along said line between the poles to a final operating position relative to said pole pieces and with selected magnetic characteristics to thereby adjust the relative strength of the magnetic biasing characteristics of said magnet with respect to each pole piece to impart selected operating characteristics to the relay.

13. The method of claim 12 wherein said relay is a type having two switches with spaced pairs of switch pole pieces and said magnet is positioned between the pairs of pole pieces of said switches.

14. The method of claim 12 characterized by and including the step of shifting the axial position of the magnetized member to a position wherein the bias produced thereby is sufficiently great as to cause single-sidestable operation of the switch.

15. The method of claim 12 wherein the adjustment of said magnetized member is such as to produce a larger amount of magnetic bias towards one pole piece while the switch retains bi-stable characteristics.

16. The method set forth in claim 12 characterized by and including the step of imposing a magnetic field of proper magnitude on said magnet to selectively partially demagnetize the magnet.

References Cited UNITED STATES PATENTS 3,114,020 12/1963 Hall 335-205 3,164,698 1/1965 Perrine 335205 2,907,846 10/1959 Wilhelm 335l79 3,076,878 2/1963 Koda 335l53 3,237,096 2/1966 Zechman 335-152 3,325,685 6/1967 Hoel 335153UX HAROLD BROOME, Primary Examiner 2233; UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,559,12 Dated may 26 1211 Invencor(a)C M. Emmons It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

' Column 5, line 27, for "1" read 5 Signed and sealed this 11th day of May 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAME. SCHUYLE Attesting Officer Commissioner of Pa 

